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TheFury

Oh, the humanity!!
Hey everyone - Calling all sundew experts!

I have four nice pygmy sundews, and I'm trying to get them to produce some gemmae so I can sustain their colonies. To achieve this, I've gradually lowered the photoperiod down from 16 hours to 9. I plan to leave it there until mid-February and then start ratcheting it up again.

This may or may not be pissing my other plants off. I have a number of tropical dews, pings, etc. in the same rack along with my pygmy dews. My pings look VERY happy (even my struggling P. moctezumae is showing signs of recovery!). But so far, my D. adelae, D. alicae, D. spatulata "Fraser Island," and D. venusta appear to be in various stages of decline. I'm quite concerned about the D. adelae and D. alicae; the D. spatulata and D. venusta just aren't as pink and dewy as I'd like them to be.

For those of you that grow sundews under lights, have you experimented with photoperiods this short? Might the plants be happier if I simply let them dry out a bit more?

I'll post some pics up soon so you can see what the deal is.

---------- Post added at 09:47 PM ---------- Previous post was at 08:48 PM ----------

As promised:

D. venusta:
IMG_0471.jpg


D. aliciae:
IMG_0470.jpg


D. adelae:
IMG_0469.jpg


D. spatulata:
IMG_0468.jpg
 
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I would go with ~10 hours as the lowest. Those plants have a ltitude between equatorial and temperate.
 
You may notice that when you reduce the photoperiod, some plants may be more succeptible to root rot. However, I know droseraguy used a photoperiod of around 9 or 10 hours for most of his dews and they all did fine- so I'm not sure why I had such problems with my D. admirabilis, D. nidiformis, and D. adlelae etc. but I think it was related to the water levels. When I watered less frequently, less of them were prone to root rot or whatever the problem was...

So unfortunately, I've since avoided lowering the photoperiod, and now I don't get gemmae anymore :(

PS it appears that your water levels may be a bit too high for the D. aliciae since they're all developing humic acid on the crown. You can try wiping that residue off to give the leaves normal growth again. Venusta and Spatulata have done better for me in comparison to others in "wetter" soils, while D. aliciae typically does what you're experiencing. I don't know what's up with the Adelae though, unfortunately. Mine weren't too happy when I had recently transplanted them, even with a humidity dome. The temps may have been too cold at the time for them to transition like they normally do into the cooler temps (when already established). Perhaps it is still recovering from the old media. I can't tell if those little white specs on the newest leaves are tiny bugs or if it's just sphagnum dust residue from the recent transplant.

How far away do you have the lights now? It looks like they're all gradually developing a bit more coloration, which is good. They could possibly all stand to have the lights even closer. Maybe a few inches closer. Higher intensity lighting tends to counterbalance the lower photoperiod's effects on my plants the year I was experimenting with the lower photoperiod, so you can see if that will help or not.
 
It looks like your D. adelae is planted in peat and sand with a topdressing of LFS.

Replant into pure LFS or LFS and perlite. I've never hadit do well in anything less than an airy media like that.

I never got into Pygmies so I cant help you with that, but 10 hours is the minimum I would go with 12 being better. Intensity is more important than duration, though, so no matter what have the lights as close as you can without encountering temperature problems.

I always grew my Drosera with my nepenthes with a year long photoperiod of 16 hours, but in the spring and summer I moved the hardier ones outside where they do best after an acclimation into full sun.
 
I would go with ~10 hours as the lowest.

In your experience, do Pygmies still produce gemmae with photoperiods of 10 hours or more?


PS it appears that your water levels may be a bit too high for the D. aliciae since they're all developing humic acid on the crown. You can try wiping that residue off to give the leaves normal growth again.

Humic acid huh? Interesting. I tried scratching at it with my finger nail last night and it wouldn't budge; I'll try my luck with a damp Q-tip tonight. Thanks for the suggestion! I'll also let my plants go longer without watering - probably gonna leave my water level around 1" and let the bin go dry for 5 or so days before refilling. Sound reasonable?

I don't know what's up with the Adelae though, unfortunately.

Yeah, tell me about it! :( This will actually be the second adelae that I've killed... that is, if this one bites the dust, too. I don't know what's going on - I thought these things were easy! It was doing well for two weeks or so... growing quickly, producing dew... and now look at it! And I believe the white specks are just residue from the transplant.

How far away do you have the lights now?

Between the actual light tube and the rim of most of my pots, I measure about 7". Also, I was wrong when I said they were T5s in previous threads. They're actually 32-watt T8 bulbs.

It looks like your D. adelae is planted in peat and sand with a topdressing of LFS.

Replant into pure LFS or LFS and perlite. I've never hadit do well in anything less than an airy media like that.

That's exactly the mixture I'm using. It seems that adelae are quite sensitive to repotting - do you think that yet another repotting in two months will push this plant over the edge? If not, I'm open to trying anything!



So, is the general consensus that it's more of a water issue than light issue at this point?

Thanks for all the responses everyone!
 
As far as i understand, gemmae production is tied directly into reducd photoperiod. Whatever i had going for November, that was perfect (10 hours). Before and after that, I had almost nothing.
 
Hey, thanks. About how close were the lights to your plants? And out of curiosity, two questions: 1) How long after your photoperiod reached 10 hours did your gemmae start forming, and 2) how long did you leave the photoperiod that low before raising it back up to summer levels?
 
Hey Fury, with my fixtures, when I use a single 2-bulb T-8 fixture then I get the bulbs within 2-3 inches of my plants for decent intensity. When I use 2 fixtures side-by-side, then I can obtain more intensity than that even when I have the fixtures 6 inches away or a bit more.

And for me, it took around 2-2.5 months before mine produced gemmae the year I switched the photoperiod to 10 hours. I actually gave up and then noticed a few weeks after changing the photoperiod back to 15 hours that a few, like D. omissa x pulchella and D. roseana had gemmae. Other species didn't have gemmae at that point though, so they may take a bit longer?

Here is an old post I had copied to my computer
The 2 quotes of interest to me were:
droseraguy: "In the fall I set the daylength to 10 hours and put in the basement 50-60 F. temps. After a few months they all seem to produce a bunch of gemmae. In the spring temps are upped to 65-70 and 16 hours of light. My D. scorpiodes is flowering with a band of gemmae around it's middle."

Here's the original thread: http://www.terraforums.com/forums/showthread.php?t=108218
 
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My plants are on a grow rack, right next to sliding glass doors. I use a timer and adjust the daylength to roughly mimic seasons. I've noticed, though, even with artificial lights within inches of the plants, they respond more to what shines through the glass doors than the fluorescent lights. I can tell that because the flower scapes "follow the sun", as it were. I won't be upping the daylength again (to 11 hours) until February.

---------- Post added at 07:18 PM ---------- Previous post was at 07:08 PM ----------

As an aside, I would water the D. aliciae from above, with purified water. That will remove the impurities and allow the new leaves to come in green, instead of black.
 
  • #10
Just a few comments regarding gemmae formation. I have never experimented in minimal daylength, and this is a good question for experiment. I hope you will continue to update with what you learn from your attempts.

In general, gemmae production needs less than 11 hrs photoperiod. Plants in habitat form gemmae during the wet season, so wet and cool is optimal. They are light hungry plants and will not form gemmae unless there is ample light. I used flourescent tubes and the rosettes were always nearly touching the tubes no more than a couple of cm away. It's pretty safe to say you cant get them close enough to the light source unless there are heat issues. Judging from the coloration of your plants, they aren't getting the light they need, and it is doubtful that there is enough to power the gemmae formation.

I always opted for a 70/30 mix of silica sand/peat.

Your plants exhibit many signs of excessive mineralization in the mix, and you should consider the issues of substrate and water purity.

I also suspect that an interrupted dark period will inhibit gemmae formation, as when a light is turned on in an otherwise dark room.

I hope these observations help you with success with these great plants!
 
  • #11
Hey, thanks! Out of curiosity, which plants in particular were you talking about when you made your comment about excessive mineralization?

I'm using a RO filter for my water, so if present, the minerals would be coming from the soil. That in itself is concerning - I tested my sand with white vinegar, and no fizz. I also rinsed my peat and sterilized it to boot. Where would it be coming from??

That's unfortunate about the light. I'll see if I can finagle a way to get my pygmies closer to the fluorescents.

I recently upped my photoperiod to 10 hours based on results folks here have had with 10 hour photoperiods and gemmae production. I don't want to chance it with a lower photoperiod based on the way these plants are looking right now.

I will certainly keep you posted on my progress through the winter season. This should be interesting!
 
  • #12
I thought I posted this, but the D. aliciae crowns are blackened. That is not unusual but the way to get rid of it is to top water them with purifid water. This ties in with what Tamlin was saying about mineralization.
 
  • #13
Yeah I believe you added that to a post on the previous page, but thanks. I just top-watered my plants today.

When top watering your plants, how long do you go between waterings? I don't really know how dry is too dry; my soil stays pretty soggy for a long time after being watered so it's tough to gauge.
 
  • #14
Every coiple few days. It's more a subjective call. For most plants (not Neps), about a 1/2-1" of water in the tray is appropriate.
 
  • #15
So you keep an inch or so in your trays all the time and then top water every few days? That's more or less what I was doing before with less than stellar results, as you can see.
 
  • #16
It varies from almost nothing to 2".
 
  • #17
Fury, the key for you (especially with the aphid problem) will be to let the pots dry out a little between waterings, as jim suggested in his last post.

Judging by how moist your media looks, your tray could probably stand to have less than a half inch of water in it. I usually only use 1/4-1/2 inch in mine in my automatic watering setup, which never dries out.

You can get away with having a higher level of constant water if the plants are water-lovers, like D. rotundifolia, D. anglica, or D. intermedia, etc. or if your plants are grown in a peat:sand mix that favors sand for better drainage. Otherwise, really good air circulation will allow you to have higher water levels as well.
However, with the current media and pot height you're using, it seems to really soak in the moisture well, so I'd just recommend using a bit lower water level and letting the tray dry out every so often.
 
  • #18
SORTED!! Thanks for all the info. The tray these dews are in is completely empty and has been for about a week and a half. Last night I top-watered all my plants. I'll go three days or so between top-waterings without letting water accumulate in the tray. Once summer comes around, I'll let the plants stand in an inch or so of water.

As for my aphid problem - I murdered them mercilessly with some kind of fruit tree spray and relished in their demise (the spray is mainly neem oil with pyrethrines, and piperonyl butoxide - all CP safe according to my research). No signs of life at this point, but some black flecks have appeared on the leaves of some of my dews - presumably struggling aphids that left their hiding spaces to die. Only fitting that they be caught in the death grip of my hungry CPs in their last pointless moments on earth bwahahaha. I'll repeat the treatment in a week or so, perhaps with slightly less enjoyment next time.

Got a link or some info on this nifty automatic watering setup you got? Sounds like a fun tinker project for a gearhead like me!
 
  • #19
FYI, my Scorps made gemmae with a 12 hour period this season. Light on at 6am, off at 6-6:30pm.
I think cooler temps also help a lot as well.
 
  • #20
Thanks tommyr! I should have gemmae in a few weeks then, if I did things right.

Alright - so my lights are now closer to my plants, I upped the photoperiod by 1 hour to 10 hours total, and I'm watering plants more judiciously.

Just an update: The humic acid seems to have cleared from the crown of my D. aliciae. It's regaining some dew and I can't tell for sure but it may have even started growing again. I lost the two smallest plants, unfortunately, but I do notice some seedlings popping up from under them. Ah, the circle of life!!

The D. adelae... still not so hot. How do I keep killing this (supposedly) easy-to-grow plant??

The D. spatulata doesn't look much different. As for the D. venusta, some of the older leaves seem to have died but it seems like new growth is happening slowly.

Thanks again for all your advice, everyone. I'll keep you posted.
 
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